It looks like NASA is about to relearn the lesson of the original Murphy’s law. According to this morning’s WaPo : “The Genesis space capsule that crashed into the Utah desert last month failed because four pencil stub-size gravity switches designed to trigger the release of the spacecraft's parachutes were installed backward, NASA officials said yesterday”.
The original, formulated in the late 1940’s, was an engineering proverb designed to prevent the exact failure experienced in 2004.
Initial tests used a humanoid dummy, strapped to a seat on the sled, but subsequent tests were performed by John Paul Stapp, then a Captain. During the tests, questions were raised about the accuracy of the instrumentation used to measure the g-forces Captain Stapp was experiencing. Edward Murphy proposed using electronic strain gauges, attached to the restraining clamps of Stapp's harness, to measure the force exerted on them by his rapid deceleration. Murphy's assistant wired the harness, and a trial was run using a chimpanzee.
The sensors provided a zero reading, however; it became apparent that they had been installed incorrectly, with each sensor wired backwards. It was at this point that Murphy made his pronouncement. According to George Nichols, another engineer who was present, Murphy, in frustration, blamed the failure on his assistant, saying "If that guy has any way of making a mistake, he will." Nichols' account is that "Murphy's law" came about through conversation among the other members of the team; it was condensed to "If it can happen, it will happen," and named for Murphy in mockery of what Nichols perceived as arrogance on Murphy's part. Others, including Edward Murphy's surviving son Robert Murphy, deny Nichols' account, and claim that the phrase did originate with Edward Murphy. According to Robert Murphy's account, his father's statement was along the lines of "If there's more than one way to do a job, and one of those ways will result in disaster, then somebody will do it that way."
In any case, the phrase first received public attention during a press conference in which Stapp was asked how it was that nobody had been severely injured during the rocket sled tests. Stapp replied that it was because they took Murphy's Law under consideration; he then summarized the law and said that in general, it meant that it was important to consider all the possibilities before doing a test. .
I’m reminded of one of my favorite books of management wisdom, Augustine’s Laws . After considering the many ways in which things can go wrong and what can be done about it, Norman Augustine reminds us that, through hard work and attention, airplanes do fly, computers do run, and in most cases technology works the way it should.
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